{"id":"UBUNTU-CVE-2026-56113","details":"dhcpcd through 10.3.2, fixed in commit 5733d3c, contains a heap use-after-free vulnerability that allows unauthenticated same-link attackers to crash the daemon by sending a crafted DHCPv6 RENEW reply with RFC6603 OPTION_PD_EXCLUDE and both preferred and valid lifetimes set to zero. Attackers acting as or impersonating a DHCPv6 server can trigger dhcp6_deprecatedele() to free a delegated child address while an outer TAILQ_FOREACH_SAFE iterator in dhcp6_deprecateaddrs() still holds the freed pointer, causing a use-after-free when TAILQ_REMOVE is reached.","modified":"2026-06-29T13:56:54.833359923Z","published":"2026-06-23T17:17:00Z","upstream":["CVE-2026-56113"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-56113"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-56113"}],"affected":[{"package":{"name":"dhcpcd","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/dhcpcd?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.0.2-3ubuntu3","1:10.0.5-1","1:10.0.5-2","1:10.0.5-3","1:10.0.5-4","1:10.0.5-5","1:10.0.6-1","1:10.0.6-1ubuntu1","1:10.0.6-1ubuntu2","1:10.0.6-1ubuntu3","1:10.0.6-1ubuntu3.1","1:10.0.6-1ubuntu3.2"],"ecosystem_specific":{"binaries":[{"binary_version":"1:10.0.6-1ubuntu3.2","binary_name":"dhcpcd"},{"binary_name":"dhcpcd-base","binary_version":"1:10.0.6-1ubuntu3.2"},{"binary_name":"dhcpcd5","binary_version":"1:10.0.6-1ubuntu3.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56113.json"}},{"package":{"name":"dhcpcd","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/dhcpcd?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.1.0-8","1:10.1.0-10","1:10.1.0-11","1:10.1.0-12","1:10.2.4-3","1:10.2.4-4"],"ecosystem_specific":{"binaries":[{"binary_version":"1:10.2.4-4","binary_name":"dhcpcd"},{"binary_name":"dhcpcd-base","binary_version":"1:10.2.4-4"},{"binary_name":"dhcpcd5","binary_version":"1:10.2.4-4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56113.json"}},{"package":{"name":"dhcpcd","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/dhcpcd?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:10.2.4-4","1:10.3.0-2","1:10.3.0-3","1:10.3.0-7"],"ecosystem_specific":{"binaries":[{"binary_version":"1:10.3.0-7","binary_name":"dhcpcd"},{"binary_name":"dhcpcd-base","binary_version":"1:10.3.0-7"},{"binary_name":"dhcpcd5","binary_version":"1:10.3.0-7"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-56113.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}